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Aeolian Sound
Aeolian sound or Aeolian tone is sound that is produced by wind when it passes over or through objects. History Historically, Aeolus was the Greek ruler of the winds, and the Ancient Greeks believed these sounds were the voice of Aeolus. The earliest known observations about Aeolian sounds from a "scientific" viewpoint were made by Athanasius Kircher in 1650. Physical cause An Aeolian tone is produced when air passes over an obstacle, resulting in trailing vortices with oscillatory behavior. These eddies can have strong periodic components, resulting in a steady tone. This phenomenon is the main topic of aeroacoustics; For air moving over a cylinder, empirical data shows that an Aeolian tone will be produced with the frequency : f_\ =\ \frac, where V is the air velocity, D is the diameter of the cylinder, and \mbox is the Strouhal number, which has a value of about 0.2. Notable occurrences Aeolian sounds can be produced in the rigging of a sail-powered ship. The vortex trails p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sound
In physics, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' by the brain. Only acoustic waves that have frequencies lying between about 20 Hz and 20 kHz, the audio frequency range, elicit an auditory percept in humans. In air at atmospheric pressure, these represent sound waves with wavelengths of to . Sound waves above 20 kHz are known as ultrasound and are not audible to humans. Sound waves below 20 Hz are known as infrasound. Different animal species have varying hearing ranges. Acoustics Acoustics is the interdisciplinary science that deals with the study of mechanical waves in gasses, liquids, and solids including vibration, sound, ultrasound, and infrasound. A scientist who works in the field of acoustics is an ''acoustician'', while someone working in the field of acoustica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
